Two of the sites that I visit frequently are cnn.com and cnet.com both have HTML5 (not Flash) videos that autoplay. This is very disruptive with the audio blasting. Currently I unable to find a way prevent that, so I resorted to a brute method of blocking ALL videos on these sites:
cnn.com:

The former just blocks the actual video file, the latter blocks the video playlist, but I found if I block the latter, the site will retry to retrieve it indefinitely.

Is there a more elegant way to block all HTML5 video from autoplay using rules (instead of blocking all video on these sites)? I use Chrome, and I have tried all the possible setting (flags), but on PC, I continue to encounter video autoplay (with sound!).

If not, is there a list I can subscribe to that specifically deal with blocking of video autoplay, even at the cost of breaking video playback on those site?